The way that you move out of your "paranoia stage" is that you learn the difference between gut reactions, which really make you less safe rather than more, and an actual sense of caution and self-care.
For instance, you really ought to get to know someone for at least a few months before even thinking of meeting them in person. For some people, it could be about a year, even two years.
Here is the best reason for keeping people in your acquaintance long enough that you trust them better than your own family: you only have to do it once. Frequently picking up and forgetting shallow acquaintances just multiplies the number of times you have to stick your neck out. If you can succeed at confirming that someone is not really either a fucking waste of your time or a mentally unbalanced individual or worse, then you hang onto them. That way, you don't have to take new risks on new people. It is gold to be able to say that you feel you have vetted someone to your satisfaction, so value it and keep it. After you have crossed that bridge, you have someone in your life that you can rely on.
Remember that the First Little Pig built his house out of straw. He was a fearful little guy because, deep down, he knew that he had not done any amount of work. The Second Little Pig built his house out of sticks. He was also a fearful little guy because he knew that half of an effort was still not enough. The Third Little Pig laughed his ass off at that Big Bad Wolf because the Third Little Pig knew that he had spent that little bit of extra time to create something stronger and more formidable, and that was why the Third Little Pig was afraid of nothing.
If you put in the right time investment to build up a friendship to a point of absolute trust, then after that, you can ALWAYS get instant gratification. You only have to make a genuinely trusted longtime friend once, and after you have done so, you are safer with them than you would be without them. Once you have genuinely trusted longtime friends, then the longer you know them, the more they become people that you could call on to help you if you ever did have any sort of crisis.
People that are post-paranoia but also possessed of some intelligence only feel as confident as they do because they have put in the hard work of building up sound, trusted friendships, and they know they have not taken any shortcuts or cut any corners.
Comprehensive vetting of a person can take months. The main red flags you should look for are:
1) beware of people that have a relatively shallow personality and whose interests never evolve. If they do not have depth, then even if they were really what they say they are, then they are not really all that worth knowing. Normal, mentally healthy people have a lot of different stages in their lives that they eventually want to go through, and they evolve and develop. They do not stay the same person they were when you first met them. They are like an oak tree: they may change slowly, but if you know them long enough, they undeniably change.
2) beware of people that make you promises or offer you things when they don't really know you all that well. An authentic person is really selfish toward strangers, and they should be. If you own a dog, you don't invite a stranger to come over and fuck your dog. That's fucking crazy. If somebody offered that to a near stranger, then what would you say if you were that person's friend and someone that really cared about that person? You would tell him that he is giving too much to someone he barely knows. Altruism is for your longtime friends, who have put in the time-investment to earn it.
3) beware of people that are too eager to tell you what you want to hear. A normal person sometimes disagrees with you, and they sometimes even tell you that you are a fucking idiot. If you get into an actual fight, that's actually a good sign. Normal people have opinions, and not all of them are the same as your opinions. It is normal and healthy for good friends to butt heads, from time-to-time. Someone that is trying too hard to be a yes-man is actually kind of creepy.
However, all three of those points come back to one principle, which is depth. You don't decide which people you should have a deep trusting relationship with, but you DEVELOP a deep trusting relationship. The raw material for those is everywhere. Almost everyone here could be translated into a good longtime friend, but they will not be uniquely YOUR longtime friend until you have put a longtime investment in them. What makes them unique is not how they were born, but what makes them unique is your history with them and how knowing you has contributed to who they are.
